feat(m3-hermes): enable kanban board + update for v0.13.0

- Add kanban config block with gateway-embedded dispatcher
  (dispatch_in_gateway=true, 60s interval)
- Update venvSitePackages path from python3.11 to python3.12
  (v0.13.0 upgraded Python runtime)
- Update checkpoints section comment for v2

hosts/m3-hermes/services/hermes-agent.nix

@@ -11,7 +11,8 @@
   # matrix-nio is installed via pip in /home/hermes/.venv but the hermes
   # process uses the read-only Nix store Python, so we inject the venv's
   # site-packages via PYTHONPATH and provide libstdc++ for libolm (e2e).
-  venvSitePackages = "/home/hermes/.venv/lib/python3.11/site-packages";
+  # NOTE: v0.13.0 upgraded to Python 3.12 — path updated accordingly.
+  venvSitePackages = "/home/hermes/.venv/lib/python3.12/site-packages";
   gccLibPath = "${pkgs.stdenv.cc.cc.lib}/lib";
 
   # Build skills using agents flake lib for hermes user
@@ -152,7 +153,8 @@ in {
         cloud_provider = "local";
       };
 
-      # ── Checkpoints / Compression ──────────────────────────────────────
+      # ── Checkpoints v2 ─────────────────────────────────────────────────
+      # v0.13.0: Single-store rewrite with real pruning + disk guardrails.
       checkpoints = {
         enabled = true;
         max_snapshots = 50;
@@ -215,6 +217,15 @@ in {
         max_spawn_depth = 2;
       };
 
+      # ── Kanban (v0.13.0 — Multi-Agent Board) ──────────────────────────
+      # Durable task board with embedded dispatcher in gateway process.
+      # Workers are full OS processes with identity, heartbeat, reclaim,
+      # zombie detection, and hallucination gate.
+      kanban = {
+        dispatch_in_gateway = true;
+        dispatch_interval_seconds = 60;
+      };
+
       # ── Matrix ────────────────────────────────────────────────────────
       matrix = {
         homeserver = "https://matrix.m3ta.dev";